Skeletal Cu 7 S 4 Nanocages Wrapped by Few‐Layered Black Phosphorus Nanosheets as an Efficient H 2 Production Photocatalyst

Superstructures with hollow cage‐like hierarchical ordering play a predominant role in various applications owing to their unique properties, such as low density, an interior void, a high surface‐to‐volume ratio, and excellent permeability for charge and mass transport. Low‐cost hollow cage‐like copper sulfide superstructures are competitive candidates for optical and electrochemical applications because of their outstanding conductivity and extensive number of active sites. Thus, we synthesized crystallinity‐controlled nanotwinned polyhedral‐skeletal‐type copper sulfide cages (Cu 7 S 4 ). Further, these cages were wrapped by few‐layered black phosphorus (BP) nanosheets using simple strategies and tested for photocatalytic hydrogen production. The BP/Cu 7 S 4 hybrid material exhibited improved hydrogen production, i. e., 0.475 μmol h −1 , which was 14‐fold greater than that achieved using pristine Cu 7 S 4 cages under optimal conditions. The enhanced activity was attributed to effective charge‐carrier separation and transportation owing to the advanced unique properties of skeletal‐type Cu 7 S 4 cages and few‐layered BP nanosheets. To the best of our knowledge, this is the first report of a BP‐nanosheet‐wrapped Cu 7 S 4 system for photocatalytic hydrogen production. This system combining skeletal hollow cages with BP nanosheets is a new, fascinating, and inspiring approach for photocatalytic water‐splitting applications.